Lithium batteries, as an indispensable energy storage unit in modern society, have always received much attention for their safety. In recent years, incidents of lithium battery explosions have occurred frequently, causing people to worry about the safety of lithium batteries. So, why do lithium batteries explode ? This article will explore the causes of lithium battery explosions and propose some avoidance measures to help people better use lithium battery products.
The chemical nature of lithium battery explosion
The root cause of lithium battery explosion is that the chemical reaction inside it is out of control, causing a large amount of heat to be generated and accumulate rapidly, eventually causing an explosion.
Specifically, lithium batteries mainly consist of four key parts: positive electrode, negative electrode, electrolyte and separator. During the charging and discharging process, lithium ions move between the positive and negative electrodes and react with the electrolyte. When abnormal conditions such as short circuit or overcharge occur inside the battery, the following chemical reactions will be triggered, leading to explosion .
Electrolyte decomposition
The electrolyte is a key component inside a lithium battery that conducts electricity and facilitates the movement of lithium ions. When a battery is short-circuited or overcharged, the electrolyte decomposes and releases a large amount of flammable gases, such as oxygen and hydrogen.
Negative electrode material reaction
The negative electrode material is usually graphite or silicon. Under overcharge or high temperature conditions, the negative electrode material will react with the electrolyte to generate flammable substances, such as metallic lithium dendrites. Metallic lithium dendrites are highly reactive and easily react with the electrolyte to generate heat, further increasing the temperature inside the battery.
Cathode material reaction
The positive electrode material is usually a metal oxide. Under high temperature or overcharge conditions, the positive electrode material will decompose and release combustible gases such as oxygen.
Thermal runaway
The above chemical reactions will generate a lot of heat, which cannot be dissipated in time, causing the temperature inside the battery to rise sharply. When the temperature exceeds the tolerance limit of the battery, thermal runaway will occur, eventually causing an explosion.
Analysis of the causes of lithium battery explosion
Short circuit and overcharge
Safety accidents caused by batteries are mainly caused by short circuits. When the positive and negative electrodes of a lithium battery are abnormally connected with very low resistance, that is, a short circuit occurs, huge current and heat will be generated inside the battery.
This excessive current and strong electrical energy release will not only seriously damage the life of the battery, but also cause a sudden increase in internal pressure for sealed lithium batteries. Due to the extremely high chemical activity of lithium ions, it may eventually cause the battery shell to rupture and burn.
The chemical characteristics of lithium-ion batteries determine that overcharging (overcharging) operations will cause safety problems. When a lithium battery is overcharged, the negative electrode cannot accommodate more lithium ions, causing the lithium ions to precipitate as metallic lithium on the surface of the negative electrode, forming the so-called dendrite lithium.
When the lithium dendrites grow to a certain extent, they will puncture the diaphragm, causing internal short circuit of the battery and damage to the isolation membrane, thus causing a safety accident.
Therefore, when using lithium batteries in daily life, we should try to avoid short circuits and overcharging. Although the charging circuits of most digital products are equipped with protection ICs to prevent overcharging, it is still not recommended to connect mobile phones or other devices to a powered charger for a long time.
Lithium battery puncture
Puncture of a lithium battery is just as dangerous as short-circuiting or overcharging. Once a lithium battery is punctured, the lithium ions inside will react violently with the oxygen in the air, which may cause a fire or explosion. Therefore, such batteries must be handled with care to avoid damaging their outer casing.
When disposing of lithium batteries or electronic products containing lithium batteries, you will usually see a specific trash can sign. Carelessly discarding lithium batteries may not only cause environmental pollution, but may also cause dangerous situations such as fires during garbage disposal.
Lithium batteries in high temperature environments
When using a device containing a lithium-ion battery, the battery may be exposed to temperatures above normal storage temperatures, especially during hot summer months or when exposed to the sun for extended periods of time in a car.
In this case, you need to avoid using the device in a high temperature environment for a long time, as this will increase the risk of internal pressure in the lithium battery, which may cause the battery to bulge or even explode.
If a laptop battery or other lithium-ion battery swells, stop using it and disconnect the power supply immediately to prevent further increase in internal pressure, and replace the battery with a new one in a timely manner.
Scientific strategies to prevent lithium battery explosion
In order to ensure the safe use of lithium batteries and prevent explosion accidents, the following aspects need to be paid attention to:
Strictly control charging parameters: Charging voltage, current and time must be strictly controlled within the battery safety range to avoid overcharging. It is recommended to use the original charger and check the charger regularly to see if it is working properly.
Avoid over-discharge: When the battery power is too low, it should be charged in time to avoid over-discharge.
Keep the battery at a suitable operating temperature: avoid placing the battery in high or low temperature environments, and avoid direct sunlight or proximity to heat sources.
Avoid external shock: Avoid the battery from severe vibration, impact or compression.
Use safe batteries: Choose high-quality lithium batteries produced by regular manufacturers, and pay attention to the production date and shelf life of the battery.
Check the battery regularly: Check the battery surface regularly for damage, deformation, leakage, etc. If any problems are found, replace the battery in time.
Use safety protection devices: Using a battery management system equipped with overcharge, over-discharge, overcurrent and short-circuit protection functions can effectively improve battery safety.
Correctly dispose of used batteries: Used batteries should be properly recycled to avoid being discarded at will, which may cause environmental pollution and safety hazards.
Lithium battery explosion is a complex phenomenon involving multiple factors . We should pay attention to the correct use of lithium batteries and avoid overcharging, short circuit, high temperature and other situations to reduce the risk of battery explosion.
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